In spite of numerous advances in medical research, cancer remains a leading cause of death in the United States. Traditional modes of clinical care, such as surgical resection, radiotherapy and chemotherapy, have a significant failure rate, especially for solid tumors. Failure occurs either because the initial tumor is unresponsive, or because of recurrence due to regrowth at the original site and/or metastases. The etiology, diagnosis and ablation of cancer remain a central focus for medical research and development.
While different forms of cancer have different properties, one factor which many cancers share is the ability to metastasize. Distant metastasis of all malignant tumors remains the primary cause of death in patients with the disease. Patients with metastatic disease are typically treated with systemic therapy, which is associated with substantial toxicity. Unless the patient presents with metastatic disease, clinical observation is typically used to prognose the disease following surgical resection. Currently, the methods to determine prognosis and select patients for adjuvant therapy rely mainly on pathological and clinical staging. However, it is very difficult to predict which localized tumor will eventuate in distant metastasis.
Since the chance for complete remission of cancer is, in most cases, greatly enhanced by accurate prognosis, it is desirable that physicians be able to determine the metastatic potential of tumors. However, the metastatic potential of localized cancers is often unpredictable. The development of methods that permit rapid and accurate detection of many forms of cancers continues to challenge the medical community. Thus a major problem in the treatment of cancer remains detection and prognosis, which enables appropriate therapeutic treatment resulting in successful treatment in many cases. Therefore, there is a great need for the identification of biomarkers that can accurately distinguish localized tumors with a high probability of metastasis from those that will remain indolent. Using such biomarkers, one can predict the patient's prognosis and can effectively target the individuals who would most likely benefit from adjuvant therapy.